Flutter Navigator.pop（context）返回黑屏 [英] Flutter Navigator.pop(context) returning a black screen

问题描述

我的Flutter项目结构如下

My Flutter Project structure is like this

Main() //Run App with MaterialApp and Routes
L HomePage() //Default route (/), with BottomNavigation
  L MoviesPage() //Default BottomNavigation Index and shows a list of movies form TMDB 
    L DetailsPage()
  L SeriesPage()
  L SupportPage()

在单击任何电影后，它都会导航到DetailsPage（）但是当我从DetailsPage（）调用Navigator.pop时，它应该回到上一个屏幕，但是没有。

After clicking on any movie it navigates forward to the DetailsPage() but when I call Navigator.pop from DetailsPage() it should go back to the previous screen but it doesn't.

Navigator.canPop（context）返回false，但是硬件后退按钮绝对可以正常工作，那么如何解决？

The Navigator.canPop(context) return false But the hardware back button works absolutely fine, so how do I fix it?

main.dart

class BerryMain extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return MaterialApp(
      home: Inferno(
        {
          '/': (context, argumets) => HomePage(),
          '/detailspage': (context, arguments) => DetailsPage(arguments),
        },
      ).home(context),
    );
  }
}

主页

class HomePage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    // TODO: implement createState
    return _HomePageState();
  }
}

class _HomePageState extends State<HomePage> {
  int _currentIndex = 0;
  final List<Widget> _childnav = [MoviesPage(), SeriesPage(), SupportPage()];

  void onTabPressed(...)

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Scaffold(
      appBar: AppBar(
        title: Text('...'),
        actions: <Widget>[
          IconButton(
            icon: Icon(Icons.search),
            onPressed: () {},
          )
        ],
      ),
      body: _childnav[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        onTap: onTabPressed,
        currentIndex: _currentIndex, //this property defines current active tab
        items: [
          BottomNavigationBarItem(
              icon: Icon(Icons.movie), title: Text('Movies')),
          BottomNavigationBarItem(icon: Icon(Icons.tv), title: Text('Series')),
          BottomNavigationBarItem(icon: Icon(Icons.help), title: Text('Help'))
        ],
      ),
    );
  }
}

MoviesPage

//Inside ListView Builder
Virgil.pushNamed(context, '/detailspage', arguments: args);

DetailsPage

//Inside MaterialApp > Scaffold > SliverAppbar > BackButton
Navigator.pop(context)

我正在使用维吉尔，但我不认为这是问题所在。

I'm using Virgil but I don't think it is the problem.

推荐答案

如果您的 MoviesPage 具有另一个 MaterialApp 小部件，则可能会发生这种情况。大多数时候，您想使用 Scaffold 作为新页面/屏幕的顶部小部件，但是如果您不小心使用了 MaterialApp 相反，没有任何警告。

This can happen if your MoviesPage has another MaterialApp widget. Most of the time you want to use Scaffold as a top widget for a new page/screen, but if you accidentally use MaterialApp instead, nothing warns you.

发生了什么事，是 MaterialApp 创建了一个新的 Navigator ，因此，如果您从具有 MaterialApp 的页面切换到另一页面，则在小部件树中现在有两个导航器。

What happens, is that MaterialApp creates a new Navigator, so if you switch from one page with MaterialApp to another, you now have two Navigators in the widget tree.

调用 Navigator.of（context）查找最近导航器，因此它将使用一个，在您的 MoviesPage 中新创建的。由于您的路线转换历史记录存储在第一个导航器中，因此无法弹出-它具有空的路线历史记录。

The call Navigator.of(context) looks for the closest Navigator, so it'll use the one, newly created in your MoviesPage. As the history of your route transitions is stored in a first Navigator, this one can't pop back – it has empty route history.

因此，黑屏。

长话短说，要解决此问题，只需使用 Scaffold 作为顶部小部件，而不是 MaterialApp 在所有嵌套屏幕中。

Long story short, to fix this, just use Scaffold as a top widget instead of MaterialApp in all nested screens.

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